Burst avalanches in bundles of fibers: Local versus global load-sharing

Abstract Bursts in bundles of many parallel fibers with stochastically distributed failure thresholds are studied. The distribution of the sizes Δ of burst avalanches has a power-law behavior, ∞Δ-ξ. When the load is shared equally among surviving fibers, the power-law exponent is ξ=2.5. When, however, the increased stresses that result from a fiber failure are concentrated to the nearest-neighbor fibers, the exponent is considerably higher, for randomly distributed thresholds ξ=4.5.